Abstract:
An online system receives advertisement (“ad”) requests for presentation to online system users. An ad request may include an identifier of a landing page identifying a source external to the online system from which content is retrieved and presented to a user who interacts with content from the ad request. The online system determines a quality score for the source based on a frequency with which online system users request content from the source via the online system and various types of interactions by online system users with content associated with the source that is presented by the online system (e.g., interactions with content associated with the source indicating user interest in the source). Based on the quality score for the source, the online system modifies a score for the ad request used by the online system to determine whether to present content form the ad request to a user.